The Korea Institute of Science and Technology (KIST), with Dr. Hyang-Tag Lim‘s research team and collaborators from Yonsei University, Korea University of Science and Technology (UST), Agency for Defense Development (ADD), and Korea Research Institute of Standards and Science (KRISS), has demonstrated a new scheme for distributed quantum sensing. The research, published in Physical Review Letters, is intended to achieve the Heisenberg scaling using multi-mode N00N states.
The core technical innovation is the application of the multi-mode N00N state to link multiple spatially separated sensors. Unlike previous approaches that primarily used single-photon entangled states, the multi-mode state involves multiple photons entangled along specific paths, which produces denser interference fringes and enhances resolution. For experimental demonstration, the team employed a four-mode 2002 state with a total of N=2 photons to estimate the average of two spatially distributed phases.
The team achieved approximately 88% higher precision (a 2.74 dB enhancement) compared to the Standard Quantum Limit (SQL), demonstrating performance approaching the ultimate precision attainable with quantum technology (the Heisenberg limit). Theoretically, the research confirms that multi-mode N00N states can reach the Heisenberg scaling (a sensitivity bound of 1/N2) using local measurements.
This achievement is positioned as a path to practical quantum sensor networks for precision metrology applications. The technology has potential implications across life sciences, the semiconductor industry (detecting nanometer-scale defects), and space observation. The research was supported by the Ministry of Science and ICT (MSIT) and the KIST research program.
Read the full announcement from KIST here and the research article in Physical Review Letters here.
October 27, 2025
